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      1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "net/disk_cache/simple/simple_util.h"
      6 
      7 #include <limits>
      8 
      9 #include "base/file_util.h"
     10 #include "base/format_macros.h"
     11 #include "base/logging.h"
     12 #include "base/sha1.h"
     13 #include "base/strings/string_number_conversions.h"
     14 #include "base/strings/stringprintf.h"
     15 #include "base/threading/thread_restrictions.h"
     16 #include "base/time/time.h"
     17 #include "net/disk_cache/simple/simple_entry_format.h"
     18 
     19 namespace {
     20 
     21 // Size of the uint64 hash_key number in Hex format in a string.
     22 const size_t kEntryHashKeyAsHexStringSize = 2 * sizeof(uint64);
     23 
     24 }  // namespace
     25 
     26 namespace disk_cache {
     27 
     28 namespace simple_util {
     29 
     30 std::string ConvertEntryHashKeyToHexString(uint64 hash_key) {
     31   const std::string hash_key_str = base::StringPrintf("%016" PRIx64, hash_key);
     32   DCHECK_EQ(kEntryHashKeyAsHexStringSize, hash_key_str.size());
     33   return hash_key_str;
     34 }
     35 
     36 std::string GetEntryHashKeyAsHexString(const std::string& key) {
     37   std::string hash_key_str =
     38       ConvertEntryHashKeyToHexString(GetEntryHashKey(key));
     39   DCHECK_EQ(kEntryHashKeyAsHexStringSize, hash_key_str.size());
     40   return hash_key_str;
     41 }
     42 
     43 bool GetEntryHashKeyFromHexString(const base::StringPiece& hash_key,
     44                                   uint64* hash_key_out) {
     45   if (hash_key.size() != kEntryHashKeyAsHexStringSize) {
     46     return false;
     47   }
     48   return base::HexStringToUInt64(hash_key, hash_key_out);
     49 }
     50 
     51 uint64 GetEntryHashKey(const std::string& key) {
     52   union {
     53     unsigned char sha_hash[base::kSHA1Length];
     54     uint64 key_hash;
     55   } u;
     56   base::SHA1HashBytes(reinterpret_cast<const unsigned char*>(key.data()),
     57                       key.size(), u.sha_hash);
     58   return u.key_hash;
     59 }
     60 
     61 std::string GetFilenameFromEntryHashAndIndex(uint64 entry_hash,
     62                                              int index) {
     63   return base::StringPrintf("%016" PRIx64 "_%1d", entry_hash, index);
     64 }
     65 
     66 std::string GetFilenameFromKeyAndIndex(const std::string& key, int index) {
     67   return GetEntryHashKeyAsHexString(key) + base::StringPrintf("_%1d", index);
     68 }
     69 
     70 int32 GetDataSizeFromKeyAndFileSize(const std::string& key, int64 file_size) {
     71   int64 data_size = file_size - key.size() - sizeof(SimpleFileHeader) -
     72                     sizeof(SimpleFileEOF);
     73   DCHECK_GE(implicit_cast<int64>(std::numeric_limits<int32>::max()), data_size);
     74   return data_size;
     75 }
     76 
     77 int64 GetFileSizeFromKeyAndDataSize(const std::string& key, int32 data_size) {
     78   return data_size + key.size() + sizeof(SimpleFileHeader) +
     79       sizeof(SimpleFileEOF);
     80 }
     81 
     82 int64 GetFileOffsetFromKeyAndDataOffset(const std::string& key,
     83                                         int data_offset) {
     84   const int64 headers_size = sizeof(disk_cache::SimpleFileHeader) + key.size();
     85   return headers_size + data_offset;
     86 }
     87 
     88 // TODO(clamy, gavinp): this should go in base
     89 bool GetMTime(const base::FilePath& path, base::Time* out_mtime) {
     90   DCHECK(out_mtime);
     91   base::PlatformFileInfo file_info;
     92   if (!file_util::GetFileInfo(path, &file_info))
     93     return false;
     94   *out_mtime = file_info.last_modified;
     95   return true;
     96 }
     97 
     98 }  // namespace simple_backend
     99 
    100 }  // namespace disk_cache
    101